Oscillator/demodulator circuit arrangement for an inductive proximity switch

摘要

An oscillator/demodulator circuit arrangement for an inductive proximity switch with a transistor amplifier stage having an input circuit containing an attenuatable resonance circuit and having an output circuit, with a regenerative feedback from the output circuit to the input circuit of the transistor amplifier stage, the input circuit of the transistor amplifier stage having a limiter branch therein, includes a double current mirror operatively connected in the input circuit of the transistor amplifier stage and including a first and a second current mirror coupled to one another in a manner that currents supplied thereby are subtracted from one another at a circuit output, the transistors in the second current mirror having a larger emitter surface ratio in comparison with the emitter surface ratio of the transistors in the first current mirror.